diff --git a/Tunnel.cpp b/Tunnel.cpp
index 9ccf4219..4b831fbc 100644
--- a/Tunnel.cpp
+++ b/Tunnel.cpp
@@ -154,11 +154,14 @@ namespace tunnel
 		else	
 			block.deliveryType = eDeliveryTypeLocal;
 		block.data = msg;
+		
+		std::unique_lock<std::mutex> l(m_SendMutex);
 		m_Gateway.SendTunnelDataMsg (block);
 	}
 		
 	void OutboundTunnel::SendTunnelDataMsg (std::vector<TunnelMessageBlock> msgs)
 	{
+		std::unique_lock<std::mutex> l(m_SendMutex);
 		for (auto& it : msgs)
 			m_Gateway.PutTunnelDataMsg (it);
 		m_Gateway.SendBuffer ();
diff --git a/Tunnel.h b/Tunnel.h
index 4328ddb3..d1d77fe9 100644
--- a/Tunnel.h
+++ b/Tunnel.h
@@ -7,6 +7,7 @@
 #include <vector>
 #include <string>
 #include <thread>
+#include <mutex>
 #include <cryptopp/modes.h>
 #include <cryptopp/aes.h>
 #include "Queue.h"
@@ -83,6 +84,7 @@ namespace tunnel
 			
 		private:
 
+			std::mutex m_SendMutex;
 			TunnelGateway m_Gateway; 
 	};